Many types of mechanical devices have been developed over the years that control the position of or the force applied to an object. For example, conventional flow control devices open or close a valve in response to an external signal to permit or prevent the passage of a fluid. In the most typical situation, the valve is connected to a rod or piston which moves in response to the external signal and which in turn seats or unseats the valve. These standard flow control devices are operated manually or by connection to a solenoid, a motor, a piezoelectric device or any other type of well known actuators. These actuators convert an applied electrical drive signal into an output displacement to operate the valve. Those actuators that have a sufficient output displacement to reliably operate the valve are relatively large and heavy such as proportional solenoids.
Many flow control devices are mounted on a mechanical robot arm for use in numerous manufacturing or assembly operations, such as spraying material onto a part or applying adhesives, sealants, caulks or other material onto a part. The robot arm must fit into relatively small places and any component placed on the cantilevered arm acts as a downward weight that restricts the length and mobility of the arm. Therefore, the size and weight of the component, for example the flow control device, is an important design issue. Smaller and lighter actuators, such as a multilayered ceramic piezoelectric device formed by a laminated series or stack of piezoelectric ceramic layers separated by a conductive film, have a small displacement, typically about 0.001 inches and a high output force, typically in the range of 300 pounds. This small displacement is frequently insufficient to reliably operate a flow control device. In order to increase the output displacement to a sufficient level, a mechanical amplifier can be used to convert the high output force of the multilayered piezoelectric actuator into an output displacement that is greater than the output displacement of the actuator itself. Of course, the amplified output displacement must be achieved under operating conditions when the mechanical amplifier is connected to the flow control device. The addition of the mechanical amplifier to the multilayered piezoelectric actuator increases the overall size and weight of the flow control device with the attendant drawbacks or disadvantages described above.
It is desirable, therefore, to have a small, lightweight mechanical amplifier that provides an output displacement that is greater than the output displacement of the input actuator. Of course, such a mechanical amplifier has other advantages and benefits when used with the other mechanical devices referred to above. However, since these mechanical devices are so numerous, it is not practical to describe herein all the advantages and benefits of such a mechanical amplifier used with these devices.